NEW YORK -- Investigators were looking for a man who witnesses
said was mumbling to himself on a subway platform before and after he
pushed another man down onto the tracks in front of an oncoming train
Monday afternoon, resulting in that man's death, police said.

The
pushed man, 58-year-old Ki-Suck Han, of Queens, tried to climb back up
onto the platform a few feet above and died after getting trapped
between the train and the platform's edge, police said.

The
incident occurred around 12:30 p.m. Monday at 49th Street and Seventh
Avenue in Manhattan, where N, Q and R trains stop, and transit officials
said the incident involved a southbound Q train.

Witnesses described the suspect as a man in his 20s wearing a white t-shirt. Police are reviewing surveillance camera footage.

Patrick
Gomez, 37, of Saddle Brook, N.J., was waiting on the platform for the
southbound train. As it pulled into the station and slowed down, he
"heard a thud that didn't sound normal."

Then he saw people screaming and running from the other end of the platform.

"They looked like they were in shock," he said.

Police
evacuated the platform within minutes, Gomez said, and back up on the
street, he saw the man who'd been hit brought up on a stretcher. He said
the man looked older, and was motionless.

"This is very jarring - suddenly, in the middle of the day in midtown Manhattan," Gomez said.

Subway
pushes are unusual. Among the more high-profile was the January 1999
death of Kendra Webdale. A former mental patient admitted he shoved her
to her death.

Following that, the state Legislature passed
Kendra's Law, which lets mental health authorities supervise patients
who live outside institutions to make sure they are taking their
medications and aren't a threat to safety.